European oak decline phenomenon in relationto climatic changes

The complex phenomenon of decline in European oak is currently triggered by changing climatic conditions and their consequences like heavy rains, local floods and pest development. Especially, pathogens from Phytophthora genus profit from soil saturation with water. They are alien invasive species, which attack and severely damage fine roots. In drought conditions occurring in the subsequent year, many oaks die as they encounter problem with water uptake. Additionally, insect defoliators followed by oak mildew infections accelerate the level of tree mortality. Secondary insects, butt and root pathogens are usually the final cause of death of many oaks. More research is needed in the direction to determine (i) measurable factors (e.g. chlorophyll florescence) that can indicate that the process of tree decline has already started, (ii) the correlation between the root decay and the crown symptoms (scanners, software), (iii) which combination of stressors stimulate the best development of pathogens that lead to the high plant mortality and (iv) the difference between the mortality caused by the native and the invasive Phytophthora species.The research was performed within the frame of LIFE+ ENV/PL/000459 HESOFF ongoing European project ‘Evaluation of the health state of forests and an effect of phosphate treatments with the use of photovoltaic unmanned aerial vehicle (UAV)’.Przemysław Szmi

Pythium sterilum sp. nov. isolated from Poland, Spain and France: its morphology and molecular phylogenetic position

In a survey of Phytophthora species associated with forest decline in Spain, Poland and France, we found three Pythium isolates, which have been characterized with internal transcribed spacer rRNA gene sequences and with classical morphological descriptors for Pythium spp. These isolates showed unique internal transcribed spacer sequences, different enough from those of any described species to justify new species status. These three distinct isolates failed to produce any sex organs with an entirely asexual reproduction and were found to represent a new species for which the name Pythium sterilum is proposed. This paper describes and illustrates the morphology of P. sterilum and presents its taxonomic position and relationships with other, related Pythium species belonging to clade

The occurrence of, and economic losses caused by Armillaria in the Western Carpathian Mts

An investigation carried out in the Western Carpathian Mountains (Ujsoły, Węgierska Górka, Ustroń and Wisła Forest Districts) demonstrated a strong relationship between dieback in Norway spruce stands and the intensity of occurrence of Armillaria ostoyae. For the most endangered site types – mountain deciduous forest (LG) and mountain mixed forest (LMG), analyses of losses of annual volume increment and of stand productivity were performed, and their financial dimensions determined. The greatest losses – of about 8 m3/ha/year for tree stands of the age of 100 years, and 400 m3/ha for the rotation period – were found for LG (Mountain broadleaved forest) site type

An unknown trees die back caused by Pseudomonas species in Switzerland

A model for tree pathogen diagnosis – Prunus domestica L. has been studied against pathogenic bacteria. An orchard of 110 trees of P. domestica showed dying back symptoms in May 2009 and nineteen of these trees were eradicated and burnt for prophylaxis. No symptoms correlated with those caused by pathogens previously observed in stone fruit die back in Europe or elsewhere (Pseudomonas syringae pv syringae van Hall, Pseudomonas syringae pv morsprunorum Lazarowtz, Phytophthora sp., Diaporthe perniciosa Marchal., phytoplasma or viruses) were not found. Interestingly, cutting the trunk in transversal sections allowed the observation of stem heart necrosis which was mostly important at the grafting point. Isolations from necrotic stem heart allowed to identify anot yet described Pseudomonas species not related to P. syringae. The method described in the paper for isolation of pathogenic bacteria and their quick an reliable identification can be also applied for detection of pathogens in forest tree plantations.Przemysław Szmi

Phytophthora polonica, a new species isolated from declining Alnus glutinosa stands in Poland

In a survey of Phytophthora associated with alder decline in Poland, several isolates of a homothallic Phytophthora spet al, which could not be assigned to other taxa including Phytophthora alni subspecies, were consistently recovered from rhizosphere soil samples. Their morphology and pathogenicity, as well as sequence data for three nuclear regions (internal transcribed spacer rDNA, elongation factor-1α and β-tubulin) and a coding mitochondrial DNA region (nadh1), were examined. The new Phytophthora species is characterized by the moderate to slow growth rate of its colony in carrot agar at 20°C, high optimal (c. 30°C) and maximum (c. 38°C) growth temperatures, formation of catenulate, often lateral, hyphal swellings, large chlamydospores in agar media and in soil extract, persistent, ovoid to ellipsoid nonpapillate sporangia and large oogonia with paragynous and sometimes amphigynous antheridia. Phytophthora polonica was slightly pathogenic to alder twigs and not pathogenic to trunks of several tree species. In a phylogenetic analysis using either Bayesian inference or maximum likelihood methods, P. polonica falls in clade 8 ‘sensu Kroon (2004)' of Phytophthor

Loss of Gramicidin Biosynthesis in Gram-Positive Biocontrol Bacterium Aneurinibacillus migulanus (Takagi et al., 1993) Shida et al. 1996 Emend Heyndrickx et al., 1997 Nagano Impairs Its Biological Control Ability of Phytophthora

Peer reviewedPublisher PD

Seven recommendations to make your invasive alien species data more useful

Science-based strategies to tackle biological invasions depend on recent, accurate, well-documented, standardized and openly accessible information on alien species. Currently and historically, biodiversity data are scattered in numerous disconnected data silos that lack interoperability. The situation is no different for alien species data, and this obstructs efficient retrieval, combination, and use of these kinds of information for research and policy-making. Standardization and interoperability are particularly important as many alien species related research and policy activities require pooling data. We describe seven ways that data on alien species can be made more accessible and useful, based on the results of a European Cooperation in Science and Technology (COST) workshop: (1) Create data management plans; (2) Increase interoperability of information sources; (3) Document data through metadata; (4) Format data using existing standards; (5) Adopt controlled vocabularies; (6) Increase data availability; and (7) Ensure long-term data preservation. We identify four properties specific and integral to alien species data (species status, introduction pathway, degree of establishment, and impact mechanism) that are either missing from existing data standards or lack a recommended controlled vocabulary. Improved access to accurate, real-time and historical data will repay the long-term investment in data management infrastructure, by providing more accurate, timely and realistic assessments and analyses. If we improve core biodiversity data standards by developing their relevance to alien species, it will allow the automation of common activities regarding data processing in support of environmental policy. Furthermore, we call for considerable effort to maintain, update, standardize, archive, and aggregate datasets, to ensure proper valorization of alien species data and information before they become obsolete or lost

Screening for Fusarium Antagonistic Bacteria From Contrasting Niches Designated the Endophyte Bacillus halotolerans as Plant Warden Against Fusarium

Date palm (Phoenix dactylifera L.) plantations in North Africa are nowadays threatened with the spread of the Bayoud disease caused by Fusarium oxysporum f. sp. albedinis, already responsible for destroying date production in other infected areas, mainly in Morocco. Biological control holds great promise for sustainable and environmental-friendly management of the disease. In this study, the additional benefits to agricultural ecosystems of using plant growth promoting rhizobacteria (PGPR) or endophytes are addressed. First, PGPR or endophytes can offer an interesting bio-fertilization, meaning that it can add another layer to the sustainability of the approach. Additionally, screening of contrasting niches can yield bacterial actors that could represent wardens against whole genera or groups of plant pathogenic agents thriving in semi-arid to arid ecosystems. Using this strategy, we recovered four bacterial isolates, designated BFOA1, BFOA2, BFOA3 and BFOA4, that proved very active against F. oxysporum f. sp. albedinis. BFOA1–BFOA4 proved also active against 16 Fusarium isolates belonging to four species: F. oxysporum (with strains phytopathogenic of Olea europaea and tomato), F. solani (with different strains attacking O. europaea and potato), F. acuminatum (pathogenic on O. europaea) and F. chlamydosporum (phytopathogenic of O. europaea). BFOA1–BFOA4 bacterial isolates exhibited strong activities against another four major phytopathogens: Botrytis cinerea, Alternaria alternata, Phytophthora infestans, and Rhizoctonia bataticola. Isolates BFOA1–BFOA4 had the ability to grow at temperatures up to 35°C, pH range of 5–10, and tolerate high concentrations of NaCl and up to 30% PEG. The isolates also showed relevant direct and indirect PGP features, including growth on nitrogen-free medium, phosphate solubilization and auxin biosynthesis, as well as resistance to metal and xenobiotic stress. Phylogenomic analysis of BFOA1–BFOA4 isolates indicated that they all belong to Bacillus halotolerans, which could therefore considered as a warden against Fusarium infection in plants. Comparative genomics allowed us to functionally describe the open pan genome of B. halotolerans and LC-HRMS and GCMS analyses, enabling the description of diverse secondary metabolites including pulegone, 2-undecanone, and germacrene D, with important antimicrobial and insecticidal properties. In conclusion, B. halotolerans could be used as an efficient bio-fertilizer and bio-control agent in semi-arid and arid ecosystems